Processes are known and practiced commercially for the epoxidation of olefins by catalytic reaction of alkenes with an alkylhydroperoxide. EP-A-193682, for instance, describes the use of molybdenum in a homogeneous catalysed reaction.
Efforts have been made by prior workers to develop heterogeneous catalyst systems useful in such epoxidations which are essentially insoluble in the reaction mixture. EP-A-421781 describes a molybdenum oxide on a solid silica carrier. Such a catalyst presents the drawback that the yield of the epoxidation reaction decreases if the same catalyst is used several times in succession. Furthermore, catalysts of this type are calcined. Calcination often causes sintering of the surface, which makes such a catalyst less readily regenerable. Furthermore, catalyst is lost in regeneration.